Ligand-targeted nanoparticles encapsulated with chemotherapeutic agents play an increasingly important role in the treatment of cancer, and are expected to become the next generation of therapeutic modality. Colorectal cancer is one of the most commonly diagnosed cancers and a leading cause of cancer mortality worldwide. Current treatment for colorectal cancer only has limited success, thus more effective therapeutic approaches for these patients are urgently needed. Development of targeted drug delivery system is necessary to effectively deliver anticancer drugs to a tumor. The development of novel methods for early detection and effective treatments for cancer is contingent on the identification of unique biomarkers on the surface of cancer cells and isolation of tumor-specific ligands with high binding affinity to these biomarkers. Peptide phage display is a powerful method used to identify peptides capable of binding to a specific cell type by whole-cell panning, resulting in internalization of the peptide that can function as a drug delivery vehicle when conjugated to nanoparticle. This allows the use of the peptide to deliver toxic payloads intracellularly to achieve therapeutic effect. However, identification of the target protein of targeting peptide is problematic because the binding affinities of the peptides are low and difficult to maintain the native binding interaction between targeting peptide and isolated target protein from whole membrane extracts.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies, especially in connection with cancer targeting peptides.